Convergence of marine megafauna movement patterns in coastal and open oceans

The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content

Convergence of marine megafauna movement patterns in coastal and open oceans

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115 (2018): 3072-3077, doi:10.1073/pnas.1716137115.The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyse a global dataset of 2.8 million locations from > 2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared to more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal micro-habitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise and declining oxygen content.Workshops funding granted by the UWA Oceans Institute, AIMS, and KAUST. AMMS was supported by an ARC Grant DE170100841 and an IOMRC (UWA, AIMS, CSIRO) fellowship; JPR by MEDC (FPU program, Spain); DWS by UK NERC and Save Our Seas Foundation; NQ by FCT (Portugal); MMCM by a CAPES fellowship (Ministry of Education)

Global tracking of marine megafauna space use reveals how to achieve conservation targets

The recent Kunming-Montreal Global Biodiversity Framework (GBF) sets ambitious goals but no clear pathway for how zero loss of important biodiversity areas and halting human-induced extinction of threatened species will be achieved. We assembled a multi-taxa tracking dataset (11 million geopositions from 15,845 tracked individuals across 121 species) to provide a global assessment of space use of highly mobile marine megafauna, showing that 63% of the area that they cover is used 80% of the time as important migratory corridors or residence areas. The GBF 30% threshold (Target 3) will be insufficient for marine megafauna’s effective conservation, leaving important areas exposed to major anthropogenic threats. Coupling area protection with mitigation strategies (e.g., fishing regulation, wildlife-traffic separation) will be essential to reach international goals and conserve biodiversity

Proteoglycan changes in carcinogen (4WQ0)-Treated tongue mucosa

The purpose of this study was to undertake preliminary analyses of the extracellular proteoglycans in carcinogen [4-nitroquinoline N-oxide (4NQO)]-treated rat tongue mucosa. Experimental rats were exposed to twice-weekly applications of 4NQO in propylene glycol for six months, after which the animals were killed. Control and 4NQO-treated tissues were subjected to sequential aqueous extractions of proteoglycans under associative and dissociative conditions, followed by alkaline cleavage of protein-glycosaminoglycan linkages to yield a glycosaminoglycan residue. Tissues subjected to 4NQO applications contained smaller proportions of proteoglycans which were readily soluble under associative and dissociative conditions. Proportionately more proteoglycan remained strongly associated with other intercellular tissue components, being released only by alkaline cleavage. These biochemical alterations in preinvasive 4NQO-treated epithelium and connective tissues, together with an observed associated change in water retention by the connective tissue, occurred prior to actual neoplastic invasion and suggest differences in macromolecular conformation and orderliness. We hypothesize that these changes are related to the phenomenon of neoplastic epithelial invasion

Antigen retrieval for electron microscopy using a microwave technique for epithelial and basal lamina antigens

The current study extends the principles of the antigen retrieval technique for formalin-fixed, paraffin-embedded tissues to transmission electron microscopy. Specimens prepared for both routine and immunoultrastructural studies were examined for the effects of microwave treatment on the immunolabeling of tissue antigens. Specimens of normal rat tongue mucosa and human oral mucosa were microwaved before immunogold labeling was done using six types of antibody (types I, III, IV, and VI collagen, laminin, and cytokeratin). Sections were cut from tissue blocks that had been fixed and embedded for either ultrastructural immunocytochemistry in L.R. White resin or routine electron microscopic morphology in TAAB resin. Compared with nonmicrowaved sections, microwave-treated, immunolabeled sections of both types of embedded tissues revealed markedly enhanced gold labeling for type IV collagen in the oral epithelial basal lamina. Moreover, microwave-treated L.R. White sections showed greater label density for type III and VI collagens and for cytokeratin compared with nonmicrowaved sections. There was variable gold labeling for laminin in both TAAB and L.R. White sections with or without microwave pretreatment and no improvement in type I collagen detection in microwave-treated sections. We concluded that postembedding microwave treatment of plastic ultrathin sections on sodium citrate buffer enhances some tissue antigens by increasing the likelihood of reexposing epitopes encrypted by a fixative-denaturative milieu. This microwave technique offers the potential of combining immunocytochemistry with enhanced exposure of antigenic markers of ultrastructural morphology in a number of extracellular sites